This invention relates to the discovery and asexual propagation of a new variety of grapevine, Vitis vinifera cv. `Sugraeighteen.` The new variety was first hybridized by David W. Cain in Wasco, Kern County, Calif., the variety being originated by controlled hybridization and subsequent ovule culture from normally abortive seeds. The new variety is characterized by its large, white, seedless berries having a desirable, distinctive, muscat flavor; crisp, juicy flesh; and tender skin.
The seed parent is the `Redglobe` variety (U.S. Plant Pat. No. 4,787) and the pollen parent is an unnamed seedling 069-172, which arose from a cross between the `Muscat Alexandria` variety (unpatented) and the `Sugraone` variety (U.S. Plant Pat. No. 3,106). The parent varieties were first crossed in May, 1990, with the date of first flowering of the new variety being May, 1992. The new `Sugraeighteen` variety was first asexually propagated by David W. Cain in Dec., 1992, in Wasco, Kern County, Calif., using cuttings.
The new grapevine variety cv. `Sugraeighteen` most nearly resembles the `Italia` grapevine variety. It differs from the `Italia` variety (unpatented) by having more nearly round berries and by possessing rudimentary seeds that are not noticeable when eaten as opposed to normal, full size, lignified seeds of the `Italia.`
`Sugraeighteen` differs from the `Sugraone`, `Perlette` (unpatented), and `Thompson Seedless` (unpatented) varieties and other commonly grown white seedless grapevine varieties by possessing a distinct and moderately strong muscat flavor somewhat similar to that of the `Italia` grapevine variety. It also differs from the above listed varieties by having much more nearly round berries than `Sugraone` or `Thompson Seedless` and by having much larger natural berry size than either the `Perlette` or `Thompson Seedless` varieties and by being more responsive to exogenous gibberellic acid applications than either `Sugraone` or `Perlette.` The new variety retains very high productivity when spur pruned.
The new `Sugraeighteen` variety has been shown to maintain its distinguishing characteristics through successive asexual propagations by, for example, cuttings.